The objective of this project is to obtain a better understanding of the structure, biosynthesis and assembly of influenza virus. During the next year we intend to pursue the following studies. We will continue to investigate the pathways utilized to direct different viral glycoproteins to distinct cell membrane domains. We have recently observed that the ionophore monensin inhibits transport of VSV glycoproteins to the basolateral surfaces of MDCK cells, whereas transport of influenza virus glycoprotein to apical membranes was unaffected. The effects of other ionophores will be compared with that of monensin to determine how different cellular transport systems are affected by various ionophores. The effects of monensin on influenza virus and VSV in MDCK cells will be compared with those observed on other viruses and other host cell types. We will continue to investigate the role of glycosylation of the HA glycoprotein on its biological and immunological properties. For this purpose, we have recently succeeded in defining conditions by which it is possible to obtain intact, nonglycosylated HA incorporated into virions in the presence of tunicamycin.